problem with idle - Honda Prelude Forum

blkvteclude · 05-29-2002, 09:08 AM

my idle is back to what it was doing ( up and down between rpms) i changed the o2 sensor and idle air sensor now i think it is the Throtle position sensory how much do they run for i need one can anyone help me out.

marcucci · 05-29-2002, 09:48 AM

Coolant level? TB/IAC coolant paths are connected properly?

The coolant level needs to be correct in both the overflow AND the radiator. If not, you will get the hunting idle.

What's the "idle air sensor?" You mean the IAC?

blkvteclude · 05-29-2002, 12:13 PM

yea i meant iac i know what the problem is it is the Throtle position sensor

BoostedH24 · 05-29-2002, 01:03 PM

Quote:

yea i meant iac i know what the problem is it is the Throtle position sensor

how did you figure that out? did the car stall at all or just idle hunt?

marcucci · 05-29-2002, 01:05 PM

Quote:

Originally posted by blkvteclude
yea i meant iac i know what the problem is it is the Throtle position sensor

How do you know?

The TPS is not adjustable on the 5g, not sure about the 4g... but I think it is not. I have yet to see one fail. The TPS should not cause a funky idle unless the stop screw for the throttle plate has been moved. If the ECU detects throttle input, it will advance the timing and the engine will rev.

A good test would be to check the timing while it's oscillating. If the timing is moving when this happens... it could be the TPS. Also check the throttle cable, if it is a hair too tight you could have the same symptom.

Lude_conduct · 05-29-2002, 02:02 PM

I'm willing to bet it's one of two problems:

-IAB valve or an air pocket in the coolant passage in the intake manifold.. have you performed the TB coolant bypass mod? If not, check your coolant level and open the bleeder screw on the top of the thermostat housing with a 10mm socket to bleed off any air in the system

-Vacuum leak. Look for any hoses which may have popped off the intake manifold, are dried up and cracked, and listen to any hissing noise while the engine is running. Are all of your accessories working correctly? Cruise control? No MIL? A vacuum leak WILL cause a rough/ocillating idle but it not noticable at part-throttle.

BoostedH24 · 05-29-2002, 02:36 PM

Quote:

Originally posted by Lude_conduct
I'm willing to bet it's one of two problems:

-IAB valve or an air pocket in the coolant passage in the intake manifold.. have you performed the TB coolant bypass mod? If not, check your coolant level and open the bleeder screw on the top of the thermostat housing with a 10mm socket to bleed off any air in the system

-Vacuum leak. Look for any hoses which may have popped off the intake manifold, are dried up and cracked, and listen to any hissing noise while the engine is running. Are all of your accessories working correctly? Cruise control? No MIL? A vacuum leak WILL cause a rough/ocillating idle but it not noticable at part-throttle.

its neither of that on my car